Gambut Kita recently met with researchers at the University of Palangkaraya who have been working within the project to measure the increased levels of peat acidification and carbon emissions that result from peatland fires in the Sebangau National Park. The park has an area of 568,700 hectares and lies just across the river from the the city itself. In doing so, we discovered that for many years, the university has also been playing an important role in rewetting and restoring this important Peat Swamp Forest (PSF) conservation area.
This April, our team met with Muhammad Idrus, the hydrology coordinator for Borneo Nature Foundation (BNF), a local organisation that shares the work of protecting the university’s Peat Forest Natural Laboratory (LAHG) over an area of 50,000 hectares. This responsibility is shared with the university’s Unit Pelaksana Teknis (UPT) and CIMTROP, who collaborate together to block canals and conduct forest research activities in the LAHG.
As we crossed the Sebangau river, Pak Idrus explained why the canals had been dug in the first place: “It is almost impossible to carry raw logs out of a peat swamp forest unless you have canals,” said Idris. But the canals drain the water content out from the surface of the soil, making it very easy for forest fires to start. In the LAHG area alone, there are 22 canals of varying lengths. “The longest canal we found was 12 kilometres long,” said Idrus.
Trending Towards Conservation and Research
Pak Idrus also spoke about the positive change he has witnessed, having seen a definite shift in the use of the area, from illegal logging, to conservation and research. Licensed for commercial logging during the 1970’s, 80’s and 90’s, the peat swamp forest was then further degraded by illegal logging and the incursion of drainage canals for the transport of raw logs. But in recent years, more attention has been paid to protecting the national park by blocking canals and restoring the natural hydrology upon which the ecosystem depends.
As a member of the LAHG patrol team, Pak Idrus is responsible for monitoring the state of the many box dams that have been installed to block the canals and slow the flow of water. Box dams hold back the water flow by creating a partial barrier or blockade in each canal.
Using Local Construction Materials
Pak Idrus told us that three types of wood are commonly used to make box dams. These are Kayu Galam, Benuas, and Belangeran. Although Belangeran is the best type of wood, it is now quite rare. And while Galam is a type of wood that is quite resistant to water, it is very difficult to use. For these reasons, Benuas is most often used, as it can resist rot for up to five years. He went on to say that each dam must be repaired if it gets damaged. “Over 800 repairs were done from 2005 to 2023. Each canal requires many blockades, and a canal with a length of 8 kilometres may need as many as 16 box dams” he said.
Construction of box dams requires a good understanding of natural hydrological field conditions. Dam construction is divided into two parts: the mobilization of the materials, and the construction of the dam. Materials are brought in when the water rises, and construction takes place when the water recedes. Thus, natural conditions are decisive in canal blocking; if the tide is high, the work must stop. If the water recedes, the materials are difficult to mobilize. These are the biggest challenges faced when blocking the canals.
Building canal blocks is also expensive. The dams are of three sizes: Type 1 (1.5 – 2m wide) costs 12 million rupiah; whereas Type 2 (2.5 – 3 m wide) costs 18 million rupiah, and Type 3 (3 – 4 m wide) costs 24 million rupiah. The LAHG area only uses Type 1.
Involving the Community
Involving the community in building box dams is vital, both to educate them about the importance of the peat swamp forests, and to create a sense of local ownership. “We always involve the local community in making the box dams; and we sometimes even involve some former illegal loggers; so as to give them a chance to reform their behaviour,” said Idrus.
But community acceptance of canal-blocking is a gradual process. Idrus said that in the past, many people damaged or destroyed the box dams in order to continue bringing raw logs out from the forest. However, it seems that, as the community now gets direct economic benefits from constructing the dams, they are also taking an active part in maintaining them.